Camshaft Position Sensor: Testing and Inspection
Camshaft Position (CMP) sensor -G40- and Camshaft Position (CMP) sensor 2 - G163-, checking
The two camshaft position sensors inform the engine control module of the position of the intake camshafts.
NOTE:
- CMP sensor 2 -G163- is located at the rear of left cylinder head (bank 2).
- CMP -G40- is located at the front of right cylinder head (bank 1).
- CMP locations.
- Remove air cleaner housing.
Checking actuation of CMP sensor
Use leads from adapter set V.A.G 1594 for the following tests:
- Push back rubber grommet at connector of relevant CMP sensor.
- Connect diode test lamp V.A.G 1527 from rear between contacts 1 and 2 to CMP sensor connector (leave connector attached to CMP sensor).
NOTE: The contacts are numbered accordingly on the back of the connector.
- Operate starter for several seconds.
Diode test lamp must flash briefly on every second engine revolution.
NOTE: Diode test lamps with a low current input do not go out completely after each actuation of the engine control module, but rather continue to glow slightly and become distinctly brighter on actuation.
If diode test lamp does not flash:
- Check power supply.
Checking CMP sensor power supply
- Disconnect connector at relevant CMP sensor.
- Switch on ignition.
- Connect portable multimeter V.A.G 1526 for voltage measurement to contacts 1 and 3 of connector.
Specification: approx.5 V
Checking CMP sensor signal wire
- Connect portable multimeter V.A.G 1526 for voltage measurement between contact 2 of relevant connector and engine Ground.
Specification: approx. battery voltage
If all readings match specifications and diode test lamp does not flash
(measured between contacts 1 and 2 with starter, connector attached):
- Replace relevant CMP sensor.
- Check wiring if readings do not match specifications.
Checking wiring between CMP sensor and engine control module
- Connect test box V.A.G 1598/31 at wiring harness to engine control module. Actual engine control module is not to be connected. Wiring And Component Check Using Test Box V.A.G 1598/31
- Check wiring from CMP sensor ....
- .... to engine control module for open circuit and short to positive/Ground.
CMP sensor -G40- (bank 1)
3-pin connector at wiring Test box V.A.G
harness, socket 1598/31, socket
1 (positive) 98
2 (signal) 87
3 (Ground) 108
CMP sensor 2 -G163- (bank 2)
3-pin connector at wiring Test box V.A.G
harness, socket 1598/31, socket
1 (positive) 98
2 (signal) 86
3 (Ground) 108
Resistance: max.1.5 Ohm
- Eliminate open circuit in wiring/short circuit if necessary.
If, after erasing the fault memory on a trial basis, a fault relating to the camshaft position sensor is still displayed although all preceding checks were
OK:
- Sensor rotor ring twisted; check phase position.
Checking phase position of CMP sensors
- Connect vehicle diagnostic, testing and information system VAS 5051 and select vehicle system "01 - Engine electronics" from list. Engine must be idling. Connecting VAS 5051 Scan Tool
Indicated on VAS 5051:
- From list -1- select diagnostic function "08 - Reading measured value block".
Indicated on VAS 5051:
1 - Enter display group
- Use keypad -2- to enter "093" for "Display group number 093" and confirm by touching Q key.
Indicated on VAS 5051:
- Check display in zones -1- to -4-.
Display Group 93:
NOTE: If display zones 3 and 4 in display group 93 remain blank, bank 1 phase position can be read from display group 91, zone 4, and bank 2 phase position from display group 92, zone 4. Specifications in each case: -6 degree CA ... 6 degree CA.
- Terminate function "08 - Reading measured value block" by touching <- key.